Astronomical Observatory: Cool Images

M83 (NGC 5236) Spiral Galaxy, John Scherer

The Southern Pinwheel Galaxy (also known as Messier 83 or NGC 5236) is an intermediate spiral galaxy roughly 15 million light-years away in the constellation Hydra. It is one of the closest and brightest barred spiral galaxies in the sky, thus making it visible with binoculars. Nicolas Louis de Lacaille discovered M83 in 1752 at the Cape of Good Hope. The nick-name "Southern Pinwheel" refers to the shape of the galaxys' major spiral arms.

The above image is a wonderful example of the way in which spiral galaxies can be captured using modern scientific equipment. The picture provided is the product of three separate images each representing a certain color wavelength (Clear, Green and Blue). The CCD (Charged Coupled Device) chip utilized by the Rehoboth observatory telescope was able to detect fine light details in the photographs as is seen in the above image. Interestingly enough, the arms of a spiral galaxy are such that they possess the hottest portions of the structure; this is why they are blue in color. Unfortunately, however, each arm is very quick to come to life and is equally quick in its dissolution--meaning essentially that, they're quick to come yet quick to go. The reason, however, that there remains a constant set of blue arms for any given spiral galaxy is the fact that they do indeed constantly replenish themselves independent of the central part of the galaxy. And because of the density of the arms, the gasses present are compressed to a point to which they are transformed, thus providing a continual source of super-hot stars. Because of the temperature of the stars (some of the hottest in the solar system) they burn out very quickly. The angular size of the above cited galaxy is approximately 513 arcseconds.